Lightning-arrester.



No 887,221. I 'PATENTED MAY 12, 1908. J. PEARSON.

LIGHTNING ARRESTER.

APPLIOATION FILED NOV. 24, 1905.

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No. 887,221. PATENTED MAY 12, 1908. J. PEARSON.

LIGHTNING ARRBSTER.

APPLICATION FILED NOV. 24, 1905.

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Apm WM TED STATES PATENT OFFTQE.

JOHN PEARSON, OF SOMERSET, WISCONSIN, ASSIGNOR OF ONE-THIRD TO JAMES F. WILLIAM- SON AND ONE-SIXTH TO FRANK D. MERCHANT, OF MINNEAPOLIS, MINNESOTA.

LIGIITNING-ARRESTER.

Specification of Letters Patent.

Patented May 12, 1908.

Application filed November 24, 1905. Serial No; 288,829.

art to which it appertains to make and use the same.

My invention has for its object to provide an improved lightning arrester which will allow a free discharge from a line to the ground, of abnormally high static charges, such as produced by lightning, but which will offer great resistance to the dynamo or line current, and not permit such flow thereof to the ground, as would short circuit the generator and thereby impair thegood running condition of the system.

The invention is particularly adapted to increase the efficiency of so-called horn lightning arresters Horn lightning arresters are at present in quite extensive use, and their general construction and operation are understood by persons familiar with this subject.

In carrying out my invention, I provide a horn lightning arrester with what Iterm av barrier In the preferred arrangement this barrier is placed between the horns of the arrester, and its bottom at-the place where the horns come nearest to each other, is of such character that while the lightning charge will force its way under the same, it will offer a very great resistance to the dynamo are which follows.

The invention is illustrated in the accompanying drawings, wherein like characters indicate like parts throughout the several views. I

Figure 1 is a diagrammatic view, showing a horn lightning arrester having my invention applied thereto, the said arrester being interposed between the ground and one of the line wires, of athree-phase alternating power-transmission system. Fig. 2 is a detail in side elevation, showing one'of the so-called barriers removed from working position. Fig. 3 is a detail in side elevation, illustrating another form and arrangement of the barrier in respect to the horns of the arrester.

The numeral 1 indicatesv a three-phasecharacter.

alternating generator, and the numeral 2 indicates the three line wires of the system of which said generator is a part.

The numeral 3 indicates choke coils interposed in the line wires 2, at the generating end of the line.

The numeral 4 indicates a conductor leadingfrom one of the line wires 2, and having its sections connected to the horns 5, of a horn lightning arrester of the usual or any suitable construction. The horns of this arrester diverge upwardly. In practice there should be a lightning arrester for each line Wire, and this arrester should be a free discharger, suchas a horn arrester. It may be here stated, however, that this invention is not limited to use in connection with polyphase generating systems, but may be used in connection with power-transmission lines or electrical conducting systems of various However, this type of arrester works to the best advantagein connection with high tension powertransmission circuits.

' The barrier which is provided in accordance with my invention is preferably in the form of a thin plate 6 which, as illustrated, in the drawings,may be assumed to be a sheet of mica, having, as shown, near its lower ortion, one or more small perforations 7. T s barrier is inter osed between theme, with the most closely positioned por tions of the two horns of said arrester. This barrier may be held in the osition stated, by a slit supportin pin 8, or y any other suitable form of ho der.

With the barrier interposed between the horns of-the arrester, as shown in Fig. 1, a lightning char e from the line being of enormously high voltage and of very small quantity or am erage will force its way through the per oratlons 7 of said barrier; While with the arrangement shown in Fig. 3, the lightning charge will force its way from one, horn to the other of the arrester under the barrier. Otherwise stated, the said barrier offers resistance to the 'passage of the dynamo are or current on account of thermal and electro-dynamic action so that it flashes upward or around the barrier, genera ing great .heat and causing the heated gases to rush upward and to carry 01' force the dynamo are up to the upper ends of the horns of more, the said barrier causes the metallic fumes which are burned by the are, from the prongs of the arrester, to pass upward or around said barrier, and hence prevents the formation of the partial conductor directly.

between the most closely positioned ortions of the said horns. Many materia s other than'mica have the properties above indicated. 1

A barrier of paper will allow lightning to flash through it, and forces the dynamo current upward; but of course when a aper barrier is employed, it must be replace each time after such a charge has-been grounded, as such paper will usually be burned up.

A very good barrier may be made of a thin piece of asbestos. When this form of barrier is em loyed, the lightningmay be made to pass rough it, and after the lightning has assed through it, the-dynamo arc will be orced upward,'on account of the-thermodynamic and electrodynamic action and the great resistance of the asbestos.

set with its lower edge very slightly below the lowermost and most closely spaced portions of the horns of the arrester. Such an arrangement is illustrated in Fig. 3, wherein the numeral 5 indicates the horns of the lightning arrester, and 6* indicates the barrier', shown as supported by a pin 8*, with its lowermost edge 6 slightly below the most nearly approaching oint 5 of the said horns. When a static ischarge occurs at .the points 5 on the horn arrester shown in Fig.

'3, the d amo urrent establishes an are at this oint and t iis arc is forced to travel up-. war on account of the thermal .and electrodynamic actions of the-barrier 6 At such time the barrier 6 interposed between the horns 5 increases the thermal action by'increasing the length of the arc, and the said barrier also increases the resistance of the are by making it longer and longer as the arc is rier, but when the dynamo arc tries to maintain itself around the bottom of such barrier, it generates such intense heat that the rising gases force. the arc upward, and cause the same to be disrupted;- or, to go out, at the up er portions of the arrester horns.

- mica barrier without perforations could .be coated with a conducting paint 6* of high resistance, but of enough, surface to allow electric currents of abnormally high frequency to pass around its surface freely.

A .very thin late of platinum on both sides of a sheet 0 'mica, but not extending as low as the lower afford an efficient arrier. It would not imortion of the mica would pedo the free discharge of the lightning .to

used to include such materials as will not be.

reduced to molten or gaseous condition by an ordinary lightning discharge.

From what has been said, it will be understood'that the barrier may be constructed A mica barrier, for instance, may be used without perforations'or holes if the barrier be.

from a great many difierent kinds of material, and may be arranged in a great many different ways. The essential featuresof the invention are thought to have been made clear from the foregoing description and statements made.

What I claim is:

1. In a lightning arrester having'diverging horns of conducting material, a barrier interposed between said horns, substantially as described. I I 4 j I 2. In a lightning arrester having diverging horns of conducting material, a non-fusible barrier interposed in the air gap between said horns, substantially as described.

3. In a lightning arrester having upwardly diverging horns of conducting material, a,

most edge approximately in horizontal line with the most nearly a proaching portions of said horns, substantia ly as described.

In testimony whereof I aflix my signature in presence of two witnesses.

' JOHN PEARscN.

Witnesses 2 H. A. LAGRANDEUR, R. S. FUNTAD. 

